Luminous tube



June 21, 1932. w, PRQUTY 1,863,996

LUMINOUS TUBE Filed Oct. 31, 1928 2 Sheets-Sheet 1 will 0. M1 111 June 21, 1932.

LUIINOUS TUBE Filed Oct. 51, 1928 r 2' Sheets-Sheet 2 w. o. PROUI'Y 1,863,996

Patented June 21, 1932 6 UNITED STATES PATENT OFFICE WILLIS O. .PBO'UTY, O1 EERMOSA BEACH, CALIFORNIA, ASSIGNOR, BY MESNB ASSIGN- MENTS, TO METLOX CORPORATION, CORPORATION OF CALIFORNIA LTD., OF MANHATTAN BEACH,

torturous rm Application filed October 81, 1928. Serial No. 816,158.

This invention relates to luminous tubes, and es eciall to tubes made from translucent mater1al,suc as glass, that have an iomzable gas filling therein, capable of luminescence or neon,

when excited by electrical energy.

'- Ordinarily, such tubes have a filling of a noble monatomic gas, such as helium, argon or mlxtures thereof; but my invention applies as well to tubes utilizing other gases or combination of ases. Such tubes usually have an mterna as pressure of about 6 m. m. of mercury. he luminescence is secured by impressing a suflicient potential difference across the column of gas in through the tube, an greatly the light emitted thereby.

- radiate heat is enhanced b the tube. The current flow through the tube of the known t pes is maintained at a low value. It has een found that attempts to increase the luminosity by increasin the current flow are not ver satisfactory. The electrodes that are utilized for impressing the potential are too greatly heated.

Itis one of the objects of my invention to make it possible to (pass a high current thereby to multiply Such excessive or large energization has other very useful effects, besides an increase in luminosity. By using a blue tube (that is, one emplo ing a mixture of a rare monatomic gas an mercury vapor), the increased luminescence also causes greater volume of ultra violet radiations. This is useful for its actinic value, as for photography under artificial light; as well as for its therapeutic value, as in the treatment of rachitic conditions.

In order to obtain these beneficial results, I arrange the tube in such a way that it can be excited by the aid of a plurality of independent pairs of electrodes, each energized by a source distinct from the others. In this way, I find it a simple matter to keep the electrodes cool. In the preferred form of-my invention, the capability of the electrodes to making them of the external type; that is, t ey form a tubular extension or cap to the translucent tube, and have a surface external of the tube that can efliciently radiate heat, while its internal surto face acts as the active electrode surface.

.tages, and has forming part of the CALIFORNIA, A

simple even for large trol the degree of energization, as by varying the number 'of pairs of active electrodes It is another object of my inventioittb make it possible to blend rays of difieiin't or complementary colors to secure a dayligh. effect, and especially by individual cor'i ro'l of the degree of luminescence of'the constituent tubes.

My invention possesses many other advanother objects which may be made more easil apparent-from a consideration of severa em odiments of my invention. For this pur ose I have shown a few forms in the drawings accompanying and present specification. I shall now roceed to describe these forms in detail, WhlCl'l illustrates the general principles of my invention; but it is to be understood that this detailed description is not to be taken in a limiting sense since the scope of my invention is best defined by the appended claims.

Referring to the drawings:

Fi ure 1 is a view, mainl diagrammatic, of a uminous system emb ying my inventiori Fig showing the structure of the preferred form of electrode utilized in my invention;

Fig. 3 shows a modified form of the system shown in Fig. 1;

Fig. 4 is an enlarged fragmentary view of an alternation form of-electrode.

Fig. 5 is a plan view, partly broken away, of an illuminating device arranged to produce substantially white light; and

Fig. 6 is a section along plane 6-6 of 2 is an enlarged fragmentary view Fig. 3, where tube 12 is shown as spiralled to orm a source of intense illumination.

The tube 11 is arranged at each end with a plurality of branches, such as 13, 14, 15, at one end; and 16, 17 18 at the other end. These branches all lead into the main tube 11, and there are as many branches at one end as the other. In the present instance only three branches are shown, but obviously, any desired larger number can be used. These branches are made long enough to accommodate the electrodes, such as 19, 20, 21, 22, 23, 24

Before ex laining the tube structure in further detail, I shall point out the advantages of the device as thus far set forth. 'Each of the plurality of parallel electrodes, operates to lead its quota of current to the gaseous filling in the tube 11. Accordingl 2 each needs to carry but a fraction of the total current, and the electrode is not overloaded. urthermore,gsince the greatest heating effect occurs at the active electrode surface (where the gas molecules make contact with the electrode) the spatial separation of the branches 13, 14, 15, and of the branches 16, 17, 18, in which. are incorporated these active sur- .faces, assists in conducting heat away from these surfaces. Convection currents of air 3 can more effectively cool the exterior surfaces of these ends 13 to 18. If the plurality of electrodes at each end would be combined to form a single equivalent electrode, the amount of exposed surface would be considgi'ably' reduced, and undue heating would res t.

This cooling effect is of prime importance.

It is secured by separating the total electrode surface into a plurality of parts. But the effect is markedly enhanced by the use of the particular form of electrode, one of which is shown in greater detail in Fig. 2. In this figure, the electrode 19 is shown as a hollow 'metal cap, inserted over' the open end of its tube branch 13, and sealed in an air tight manner therein. ,This leaves a large exposed metallic surface, directly in thermal conductive relation to that portion of the structure which developes the heat. Of course, internal electrodes could also be used, such as shown in Fig. 4 for example. In this form, metal tube 32 serves as an electrode, and is sealed in the enlarged end 33 of the corresponding branch 34. A lead or support 35 is sealed into squash 36 to support and conduct current to electrode 32. A glass ring 37 can also be provided if desired, at the free end of the electrode to assist in maintainmgclearance between the electrode and the tu e.

The manner in which the pairs of electrodes can be excited is diagrammatically illustrated in Fig. 1. are connected across the high potential side of a step-up transformer 25. This transfront of the Electrodes 19 and 22' 17 18 help to keep the transformers insulated from one another, and to keep them properly operating in parallel, for any short circuiting current, say between electrodes 19 and 20, must find its way through the two branches 13 and 14.

The de ee of luminescence can obviously be varied y operation of switches 26, 29, and 31, whereby any one or more of the transformers can be rendered active, while the rest are left inactive. Thus for ordinary illumination, one transformer alone can be used; for higher degrees of illumination, additional transformers can be energized in succession. This capability of varying the degree ofluminescence is of conslderable importlajnce in therapeutic and photographic wor The division of the active electrode surface into a number of parts makes it possible to energize the tube 11 to an intense de ee without' an erous heating orsputtermg. The intense 1 lumination that results therefrom is maintainable indefinitely. Furthermore, there is no danger that any hot spots will develop on the active electrode surfaces, which hot spots have been noted to occur rather fre uently in electrodes that are overloaded. ese hot spots are due to the preference sometimes exhibited by the current to concentrate at a definite locality on the electrode. With multi 1e electrodes, this danger of a concentrated harge seems very materially lessened.

Due to the fact that I can vary the degree of luminescence in a sim le manner, it is possible accurately to blend rays of complementary colors to secure substantially white light. For this purpose, an arrangement such as illustrated in Figs. 5 and 6 can be used. A box 38 having a curved reflector 39 in front serves as a support for all the tube parts. In reflector are supported in any appropriate manner, a plurahty of luminous tubes of different or complementary colors, at least one of said tubes being constructed and controlled as in Fig. 1.

Thus for example, a convoluted tube 41 is shown, of indefinite length, having a plurality of electrode extensions 42 at one end; and extensions 43 at the other end. These can be bent to extend downwardly through apertures 40 in reflector 39. 'ljhe controlling and 130 energizing devices, as illustrated in Fig. 1, can be located in box 38 back of reflector 39, or in any other convenient location.

This tube 41 can be caused to emit a blue light, as by providing it with a filling of argpn or neon with a few drops of mercury. ts intensity can be regulated by the control mechanism. 'In"order to secure white illumination, I provide another tube 44 arranged between a pair of convolutions of tube 41 and emitting'a complementary color, such as red. This tube also has extensions, such as 45, that project back of reflector 39. through apertures 46.

By appro riate manipulation of switches 26 29, 31, t e intensitynof illumination of tube 41 can be controlled, so that the correct amount of blue light' white illumination an to complement the light emitted by tube 44. Such an arrangement is of considerable value for motion p cture photography; and especially when pictures are made with sound recordings, since the tubes are silent in operation.

I claim:

1. In a device of the character described, a tube having a plurality of branches at each end, an electrode associated with each of the branches, and means for separately 1mpressing a potential difference across separate pairs of electrodes, each pair including an electrode respectively at each end of the tube.

2. In a device of the character described, a tube having a plurality of electrodes at each end, and having a gaseous filling capable of ionization, and means ,for separately impressing a potential diiierenceacross separate pairs of electrodes, each pair includ ng an electrode respectively at each end of the tube. o c a 3. The combination as set forth in claim 2, with the addition of separately controllable means for energizing each pair of electrodes.

.4- In a device of the character described. a tube having a plurality of branches at each end, an electrode of the exterior type located at the end of each branch and having an internal active surface, and means for separately impressing a potential difference across separate pairs of electrodes, each pair including an electrode respectively at each end of the tube. y

5. In a device of the character described, a tube having a pluralit of electrodes of the external type at each en and having a gaseous filling capable of ionization, and means for separately impressing a potential difierence across separate airs of electrodes, each pair including an e ectrode respectively at each end of the tube.

6. The combination as set forth in claim 5, with the addition of separately controllable means for energizing each pair of electrodes.

7 In a device capable of use for providing I intense illumination for therapeutic or photorovided for forming graphic purposes, a tube having a gaseous filling in which there is included a monatomic gas of the noble group, and means for intensely energizing said gaseous filling, includmg a series of electrodes at-each end of the tube, and means for selectively energizing said electrodes in pairs across the tube.

8. In a device capable of usefor providing intense illumination for therapeutic or photographic purposes, a tube having a gaseous filhng in which. there is included a monatomic gas of the noble group, and means for intensely energizing said gaseous filling, includmg a series of electrodes of the external type at each end of the tube, and means for selectively energizing said electrodes in pairs across the tube.

0 9. In a device capable of use for providing intense illumination for therapeutic or photographic purposes, a tube havin a gaseous fillmg m which there is include a monatomic gas of the noble group, and means for intensely energ zing said gaseous filling, including a plurality of branches for the tube at each end thereof an electrode associated with each branch, and means for separately energizmgseparate pairs of electrodes, each pair including an electrode respectively at each end of the tube.

10. In a device capable of use for providing intense llumination for therapeutic or photographic purposes, a tube having a gaseous filling in which there is included a monatomic gas of the noble group, and means for intensely energizing said gaseous filling, includmg a plurality of branches for the tube at each end thereof, an electrode of the external type, associated with each branch, and means for separately energizing separate pairs of electrodes, each pair inc uding an electrode respectively at each end of the tube.

11. In a device of the character described a plurality of luminous tubes, one of sai tubes having a plurality of pairs of electrodes, the electrodes in each pair being at opposite ends of the tube, separate means for exciting both tubes, and means whereby the number of pairs of electrodes that are active in the said one of the tube can be controlled.

In testimony whereof I have hereunto set my hand.

O. PROUTY. 

